MAREN

Multi Agent Robotics Environment Based on Gazebo and ROS. For Gym integration refer here

Prerequisites

1. ROS Kinetic
   Install ROS kinetic by following the instructions here.
   If you installed the minimal version of ROS, then make sure you install the following packages as well.

   pip install --user python-rospkg catkin_pkg
   
   sudo apt install \
   ros-kinetic-trajectory-msgs \
   ros-kinetic-control-msgs \
   ros-kinetic-std-srvs \
   ros-kinetic-nodelet \
   ros-kinetic-urdf \
   ros-kinetic-rviz \
   ros-kinetic-kdl-conversions \
   ros-kinetic-eigen-conversions \
   ros-kinetic-tf2-sensor-msgs \
   ros-kinetic-pcl-ros \

2. Classic Dependencies

   sudo apt install python3-defusedxml python3-vcstool

3. Gazebo (>=7.0.0)
   Gazebo is already installed with ros-kinetic-desktop-full.
   If you installed some other configuration for ROS make sure to install Gazebo as well as Gazebo-ROS pkgs.

   • Install gazebo from here.
   • Gazebo-ROS packages from here.

Setting up

Setting up is easy. Just run

python setup_catkin.py <environment-name> #kobuki_simple_world

here <environment-name> corresponds to the environment folder's name that you want to setup.
As of now there is only one environment in the repository, but you can always get creative and make your own. You can also contribute by sending a PR (pull request) with your environment and we'll make sure to merge it if it checks out.
Running this script will automatically create a catkin workspace in the <environment-name> folder.
Be sure to source the devel/setup.bash script after this step.

When this is done you can simply run the env_spawner.py script:

python env_spawner.py <environment-name> #kobuki_simple_world

You should now see a gazebo window popup with three kobuki bots.

Creating your own environments (God Mode!)

To create your own environments in MAREN, follow the steps below (Here we are going to assume your current working directory is MAREN):

• Create a new folder with your environment name (seperate words with underscores for consistent naming convention)

  mkdir Environment/some_awesome_environment

• Add a packages.repos file consisting of all your ros packages that you'll need for the environment or, edit edit the packages.repos from the default kobuki_simple_world environment.

Example:

repositories:
  <pkg1-name>:
    type: git
    url: <github-repo-link-to-pkg1>
    version: <branch-name>
    
  <pkg2-name>:
    type: git
    url: <github-repo-link-to-pkg2>
    version: <branch-name>

NOTE: If you have packages installed in your main ros workspace @(/opt/ros/kinetic/share), they will still work with MAREN. But its advised that you specify all the packages that your environment depends on, in your project's packages.repos so that its easier for your teammates to set MAREN up and they don't end up hating you forever. 😁

• Sometimes you may want to make some changes to the files inside the packages. To do so, just create a folder called mods inside your environment and add the files that are to be modified. Make sure you follow the exact tree stucture of the files. Please refer to the mods folder in kobuki_simple_world/assets as an example.

Example:

If you want to make changes to the file kobuki.urdf.xacro thats resides in catkin/src/kobuki/kobuki_description/urdf/kobuki.urdf.xacro, just put your modified file to mods/kobuki/kobuki_description/urdf/kobuki.urdf.xacro. Here catkin_ws and mods are directory siblings.

Config Dissection:

• Add a config.yaml file to your awesome environment. It should look like this:

num_agents: 3
agent_ns: kobuki
world_launchfile: kobuki_simple_world.launch
world_file: simple.world

roslaunch:
    onetime: null
    roslaunch_per_agent:
        $launch/kobuki.launch:
            model: $NS
            robotID: $ID
            y: $ID
            x: 0

run_scripts:
    onetime: null
    run_scripts_per_agent:
        $scripts/KobukiTfBroadcaster.py:
            - $NS_$ID
catkin_ignore:
    kobuki: 
        - kobuki_keyop
        - kobuki_controller_tutorial
        - kobuki_random_walker
        - kobuki_auto_docking
        - kobuki_controller_tutorial
        - kobuki_node
        - kobuki_testsuite
        - kobuki_safety_controller
    kobuki_desktop:
        - kobuki_qtestsuite

• num_agents: self explanatory, the number of agents that you need to spawan in the environment
• agent_ns: the namespace of the agents. Every agent would be given this namespace as prefix, followed by its id. Eg. kobuki_1, kobuki_2.
• world_launchfile: the launchfile of the world, we recommend that you use an empty_world.launch file. Needs to be in <env_name>/assets/launch directory.
• world_file: the world file to pass to yhe above launch file. Needs to be in <env_name>/assets/worlds directory.
• roslaunch and run_scripts: mention all the launchfiles/ python scripts that you need to launch here, either in onetime or in roslaunch(run_scripts)_per_agent category. If you want to launch something from another package mention it as <pkg>/<launchfile> followed by parameters. For files placed inside the <env_name>/assets folder, you can access them by adding $ to whatever needs to be accessed. Eg. $launch/a.launch would refer to a file with path <env_name>/assets/launch/a.launch.
  • parameters to launchfiles and scripts can be provided as:
    • keyword a: 4
    • unnamed - a
    • no params required null
  • onetime: launchfiles/scripts placed inside are launched only once per environment.
  • roslaunch_per_agent: launchfiles/scripts placed here are launched for each agent spawned in the environment.
• If for some reasons you want to keep your environment workspace lean and want to include only a bunch of subpackages from the repositories mentioned in your packages.repos then you can add the names of packages to ignore inside your config.yaml file (shown above).